Trainer control loading device



July 1l, 1950 R. w. JENNY 2,514,606

TRAINER CONTROL LOADING DEVICE Filed Aug.. l, 1945 INVENTOR. ROBERT W. .JEN NY Bmw du? ATTORNEY `zero. `planes become more' and more difficult to actuate Patented July 1l, 1950 UNIT ED S TAT ES OFFICE TRAINER CONTROL LQADIITQG:- DEVICE Robert W. Jenny, East Paterson, N. J., assigner to Curtiss-Wright Corporation, TBlooineld, -N.J., a corporation off Delaware Application August 1, 1945'Seriiillllml 608,200

The 'invention'rel'ates to an improvement 'in .apparatus 'for acquainting student pilots with 'of` movement of the different manual controls in an actual airplane whenits airA speed is low and the' restraint disappears as thespeed approaches On the Vother hand the controls of airwithiincreasing speed `due rtothe increase in `air resistance imposed on the ailerons, rudders'elevators andlike movablevparts exposed tothe -air currents.

It is an object of @the present disclosure lto Vprovide a simple and improved 'form of device constructed and arranged to impose on `oneor more of the simulated aircraft controls #of -an aircraft trainer such a'degree` of resistance tothe manually fimposed movement as will approxi" mately-correspond'in its intensity of resistance to what'the student would have to 'operate against if'in Yan airplane actually flying at any assumed speed.

The invention discloses in combination with 'the usual ytrainer controls lsimulating the real controls and which'include work arm levers, 4an

yarrangement of balancing springs engagingithe leversin spaced relation to the `fulcrum anddisposed so Vas to be in balanced relation, that is infposition not to impose any load on the control vwhen the same-is in itslnrmalzero position,but which willimpose a load gradually increasingin magnitude with increase in displacement of the control from its zero position and gradually increasing in magnitude Withincrease in the asofturnof the controls and thus by varyingthe -leverage arms through which the springs loperate to vary the i-ntensityfofpull of the springs. vIn

trainers of this type itis vknownto utilize a speed indicator operated by an air speed indicator motor for visually indicating to the operator the speed atwhich heis assumed to be moving. In

-the instanty case the motor is utilized' to'impose La speed'factoron the operation ofthe balancing springs, that isa shifting ofthe point of application of power by the springs on thecontrols so that with increase in simulated speed there will be an increase in the load imposed on the control or controls as it or they move awayfrom its or their 'zero "or"noniload position. The stick load varies with the air speedsqua-red. This mechanism inherently provides vthe""squarir1g -sothe -motor--may'be operated directlywith changein "air speed insteadfof withair speed squared.

y `More^specifica1ly described the inventionfeatures means eontrolledby'V said motor for varying the leverage or ywork `varm -'through 'which power iis applied to' the controlsat different assumed air speeds. As the stickload varies with the-air speed squared, the spring *load adjusting means cherein disclosed providesf or "the squaring so vthat the motor may be operated-with direct change of yair speed andwithou't necesstyvof the 'motor squaring the speed. `In this way'high costs of variable electric vnflw'clian-ism `is avoided.

Various other objects andadvantages of the in'- 1 vention will beV in part 1 lobvious'from an "inspect--` ltion of'the accompanying drawings and -inpart willebe" more 'fully' set forthin the following particular descriptionL of onevf'orm of device embody- Ving the invention, andthe invention also consists in certain new andrnovelf'features offconstruction and combination of aparts hereinafter set --forth the accompanying drawings: Fig. 111s a longitudina1 sectional "view taken through a preferred embodiment of the invention parts ina simulated cruising position;

`Fig.12 saplanview 'looking down upon fthe ylii-g. 3 is a-detail-viewin side elevation of the lcontrol's'ticlrof 'the preceding figures shifted-into position-to simulate Aa rvforwardd'ive andy at an Fig. 4 is a detail perspective viewof the slider onthe stick of the preceding figures;

Fig. l5i-sa detail-view inplan of the rudder control-of Figs. '-1 landVZshifted into position to simulate 'aba-nk -tothe'rightfand at a decrease 'in assumed-airspeed,` and Figx vis-al detail perspective view of the slider on i the-'rudder controls.

In the drawingsl and referring `iirstto-fligs. '1-3 vthere fis disclosed k a stick l0 Ysimulating the conventionalaileron-elevator `control 'of aircraft and pedals Il and I2 simulating a conventionalrudder'control of aircraft all'mounted on a support Af3 which-mayb'elletinto the'ziioor of the'trainer cockpit. The Vcorl'lp'lete trainer includes a simulated air speed'indicator (not shown) calibrated Vin'terms of `air speed units and controlled'by an air speed indicator motor I4 in 'turn controlled by rheostats, switches and like circuit completed parts actuated by the simulated stick I0, rudder bars I I and I2 and other student controlled parts not particularly involved in this disclosure.

For instance the stick I functions through connections not herein shown when shifted from its normal upright or zero position shown in Fig. l to simulate airplane control actions such, for example, as a lbackpressure on the stick III for simulating climb causes a resetting of the motor I4 and a reduction in the air speed indicator reading. Forward pressure on the stick I0 as shown in Fig. 3 simulates diving and causes a resetting of the motor I4 to turn its shaft in the opposite direction and a corresponding increase in air speed indicator reading. Likewise, lateral shifting of the stick III and shifting of the pedals II-I2 for simulating banking and turning adjusts the setting of the motorI4 and a corresponding resetting-,of the air speed indicator gandof other instruments forming partof the complete training machine.

The mounting for the stick I0 permits universal articulation and includes a gimbal ring I5 of rectangular form having oppositely extending tubular` trunnions I6 and I1 projecting forwardly and rearwardly therefrom and journalled respectively in bearings found in a pair of cross plates I8 and I9 forming part of the support I3 and disposed for rotation about a front to rear .axis a-b. The lower end of the stick forms a long inverted U-shaped yoke journalled in the ring I5 and mounted on pins 2I--22 for rotation about a transverse axis c-d at right angles to the axis a-b.

The two sides of the yoke provide a guide between which is mounted a rugged block 23 separately shown in Fig. 4 and hereinafter sometimes referred to as a stick loading point slider. Also mounted for free rotary movement between the sides of the yoke is an upstanding pulley 24 about i which is trained a cable 25. The pulley is placed l in the vertical plane containing the axis a-b and is disposed so that the point of the cable with the pulley is located as close as possible to the intersection of the axes of the roll and pitch stick movements indicated respectivelyby the axis a-b Y and c-d.

trally thereof with a deep recess 32 and a narrower recess 33 for receiving respectively the pins 2 I-22 and the axle of the pulley 24 in those cases where the slider is shifted upwardly higher than is shown in Fig. 3. The slider also includes front and rear plates 34 and 35 lapping respectively the front and rear edges of the yoke 20 and form- Iing channel-like members for receiving the yoke arms.

The simulated rudder pedals II and I2 are mounted forwardly of the sticky I0 and between the pedals and stick is a turntable 36 mounted for rotation about a vertical axis e--f normal to and intersecting the axis a-b. The table is ,somewhat T-shaped in plan and includes a head ,portion formed of a pair of laterally extending. arms 31 and 38 connected respectively by links 39 and 40 with rocking arms 4| and 42 depending from the pedals II and I2. The stern portion of the T-shaped turntable is provided with guiding tracks in the form of two upstanding parallel plates 43 and 44 extending from front to rear and on which is slidably mounted a simulated rudder bar loading point slider 45. The turntable is journalled for rotary movement about the axis e-f on a king pin 46 journalled in supports 41 and 48 formed on the support I3.

The slider 45 is of H-form as shown in Fig. 6 and includes a top plate 49 overlapping the plates 43-44 and a bottom plate 50 underlapping these plates and forming at opposite sides channels for receiving the two guide plates.

A pair of balancing springs 49 and 50 of the coiled type are disposed in a horizontal plane and extend forwardly and respectively left and right from the slider 45 as best shown in Figs. 2 and 5. The adjacent ends of the springs are secured to the slider by means of a stud 5I and the ends are arranged to move therewith in a general front to rear direction and their outer ends 52 and 53 are xedly secured to the opposite ends of a cross strip 54 forming a xed part of the support I3.

The motor I4 is provided with a threaded shaft 55 on which rides a running nut 56 in the form of a long bar extending transversely of the supporting frame I2 and held thereby from rotation. A pair of parallel reach bars 51-58 are secured at their rear ends to the running nut and are connected at their forward ends by a shiftable cross bar 59. A connecting rigid reach bar 60 extends from the cross bar 59, through the bore of the trunnion I6 and is secured at its opposite end to a floating connector 6I. The exible cable 25 extending from the connector is passed over and downwardly about the pulley 24; is passed under and upwardly about a pulley 63 journalled in the lower portion of the yoke 20 and has its upper free end 64 secured to the slider 23 by means of a bar 65 extending between the wall plates 39-3I. A second cable 66 has its forward end 62 secured to the slider 45, is passed forwardly and upwardly about a pulley 61 carried by pin 68 mounted between the plates 43 and 44, is passed rearwardly therefrom through the trunnion I1, and has its rear end 69 secured to the connector 6I at a point between the pulley 24 and the rear side of the ring I5. In this waya movement of the motor controlled runner nut and associated reach bars 51-58 in one direction, say to the right of the showing in Fig. 1 will cause slider 23 to be elevated towards its Fig. 3 position, and the slider 45 to move from right to left or rearwardly towards the Fig. 5 position. A movement of the running nut 56 from right to left, that is in the opposite direction, will permit thev slider 23 to be lowered and the slider 45 to move outwardly towards the right. l 1 In operation and referring first to the operation as influenced by the stick I6, and assuming the motor I 4 to be idle for simulating zero or constant air speed and thus the slider 23 fixed in its spaced relation to the axes of articulation of the stick, it will be seen that the springs 26 and 21 while even under very light load act to ghold the stick upright in its normal zero position. In

vthe event the stick is shifted in any direction from its zero position the spring which thus zbecomes elongated acts to resist this shifting operating through a Work arm measured by the distance between the slider 23 and the plane which contains the axis of the trunnions I6-I1 and the pivot pins 2 I-22. To this extent the instant 'in-r the-springs.

fagsiagleoa disclosure functions 'generally'` as7 does lthe1"'eset ting springs in conventional rforms off-airplane stick-controls.

`The distinctive lifeature vof the present disclo- 'su'reis that means -areprovidedsuch as themo'tor 1I 4fto-shift thevslider 23 vup or down fromthe posi'- tionf'shown in'Fig. l andy thus varythelevera-ge distance at which its'associated springsl applyfa load: on the stick. Themotor I4 thus-controls the degree ofmanual--l'oad' necessary to-'displace ,A

"on slider 23.A against the resistance of thesprings 26-21 and causes the slider toA assume-af lower position on the yoke 2B and thus anincrease in the lever len-gth between the new position of the innerfends of the springs 2S-2l and the plane containing the axis of rotation of'rthe stick'f'with a result-ingchange inthe Vspring'rate of'tl'ie load- 'ifig-A system; This means-that the springs! react lover 'alongerwor-k armi than "before, and'thus 2.5

with an increase in leverage effect, so that'a Y"greater manual -forcemust kie-exerted on lthe-'stick 'tor'nove the-same than wouldbenecessaryundr lower simulated -air speed-conditions. l

y '1l-'orl another example, assumefa reduction 1in. j'sim'ulated air speed approaching.y a stallingp'osition, then-the .motorshaft willltu'rn aiew-revolutions in the opposite direction to cause a left to right shifting of the nut'56. This releases the tension -on cable permittingthe springs 28-21 vtoA draw on the-sliderw-andilift? yit into drV towards the elevated position shown in Fig. 3 or even further upward beyond this position. This means that the springs react over a shorter work arm than before, again measured by the distance between the axis of Ipins 2 |-22 and the point of application of spring load. The distan-ce is relatively short as viewed in Fig. 3 and would of course practically reach zero when the slider reached its point of maximum elevation with the pins 2 l22 received in the slots 32. It is thus seen that as the slider is elevated toward its limiting position a less and less manual force need be exerted on the stick than was necessary when the slider was more remotely located relative to the axis of turn of the stick,

Similarly and with reference to the operation as influenced by simulated rudder control, and assuming that a foot pressure on the pedals H and I2 has caused the bar formed by the arms 31 and 38 to assume an angled position as shown in Fig. 5, this will react onthe turntable 36 to similarly cause it to assume an angled position rotating slightly about its axis ef. The springs 49 and 5D will resist this turning of the turntable with a force proportionate to the distance between the axis of turn e-f and the point at which the inner` ends of the springs `i5- 50 engage the slider 45. As the cable B5 attached to this slider t5 is likewise attached to and partakes of the movement of the cable 25, it 'will be seen that the slider will be shifted relative to the axis a-b, to the same extent that the slider 23 is similarly shifted relative to the axes of articulation of the stick lil. This means that at increased simulated air speed there is a corresponding increase in intensity with which the springs 4E and 5D resist the foot imposed load, and on the contrary as the simulated air speed decreases towards zero the spring load on the fsir'nu'lated"J controls, either stick orl rudderAv pedals,

are'correspondinglydecreasedtofzeroload.` f '2 It is also appreciated that afsliiftingloonefend of fthe 4spr-ing while the 'otherfend'V1 is held'fiixed 'willfichani'ge `the length and;- thus vary :the effectivepull offthe-spring;` ,"For instance -thelength off'tliesprings Z3 aridliZ-l is longer in`Fig. '-1 than fin-*Figa'B and thus the spr-ings in the Fig. f-I'fposi- `ltion ve'xe'rt af greater -pull onthe i stickf than inthe Fig. f 3J .-position. -In' lthis way lthe 'displacement 'of ythe-inner ends of t'heesprings outwardly increases the manual `forcenecessary to dis'piaceithees-irick -I0`1`both ley-virtue of lthe longer lever arm aswell "-as bye virtue ofit'he'fuse of 'stronger Springs. Itiis Wit-him the scope@ ofthefdisclsure tof-sos'eleetthe:

"typeland size o'ffv springs usedf-softnat, witnffsayfa vvsingl'e''rotaticirrf`ofttheunotor, the inner-end-of'f-the `springs*moveJafunit"distancelto' impose-a unitin- 'crement ofi additionalad', each springfwould by "reasonf of itsl increasedi length` impose'fthe saine unitfncrement' of additional loa-d, In this way eachl rotation" of the-motor' would 'improve onf the stick va 'resistance` to r movement whichv would be i the square` of 'such' unit increment-sof* additional load; v

vB'yjlrneans 'of 'adevice or thecharacter disclosed it is possiblefto'fsiinulate Zero* stick/load conditions' with- -no slack in-`- the interconnected lparts--giving j indication'y f'Y asmooth* continuous loading with increase -in= speedA andthe retention of Zero 'loadlatfneutral 'stickA positic'snat all speeds.

Due to the disposition of the springs, the method oimoving-the `slider `her'einffeatured andthe fact 7that-stick load is varied'bylocation'of thepoint of application of the loadin'stead'of proportionally' stretching the springs,` the sy'st'emisoperafblef' with less power fromy the motorthan'fwould be the case if the motor had to pull against the full spring load.

I claim:

1. In a grounded machine for training aviators, the combination of a stick mounted for universal articulation and simulating a similar form of aileron-rudder control on an airplane, a rudder pedal simulating the rudderpedal of an airplane, a turntable located between the stick and rudder pedal and operatively connected to be turned thereby, a slider mounted on the turntable for front to rear movement along a line intersecting the axis of rotation of the turntable, a pair of balancing springs normally under tension having their adjacent ends secured to the slider to move therewith, extending outwardly in a general lateral direction therefrom and having their outer ends fixed in space and disposed when the turntable is turned to increase the tension on one of the springs while releasing the tension on its companion, a second slider mounted on the stick for vertical movement to and fromA its axis of articulated movement, a second pair of balancing springs extending in a general forward-rearward direction and disposed when the stick is shifted in any direction from normal toincrease tension on one of the springs while decreasing tension on its companion, said second'v pair of springs having their adjacent ends se cured to the second slider to move therewith and having their other ends secured in space, a motor having a threaded shaft extending in a forward direction therefrom, a runner nut on the shaft, flexible means extending from the nut to the second slider to control its relation to the axis of articulation of the stick and a second flexible means connecting the first named slider to the first named exible means whereby the motor through th tw k sliders controls therleverage through which each spring acts on its lassociated. stick and rudder pedal..I y

. 2. In a grounded machine for training aviators, the combination of a pair' of manually actuated controls, one comprising a stick and the other a rudder control simulating corresponding controls of an airplane, two pairs of balanced springs, one pair associated with the stick and tending to maintain the same in its normal upcontrol means for simultaneously adjusting the active length relation and angularly ofv each spring and the other pair associated with the rudder control, tending to maintain the same in kl0 right position and provided with a first tension its normal position and provided with a second tension control means for simultaneously adjusting the active lengthrelation and angularity of each rudder controlling spring and a single control operatively connected to both the first and second control means for simultaneously adjusting the tension on all four springs and for shifting their point of application of power relative to the stick and rudder control respectively.

3. The device dened in claim 2 and in which the single control includes an electric motor, a

threaded shaft turned thereby, a runner nut on the shaft and a flexible connection between the runner nut and the point at which each pair of springs engage its associated stick and rudder control relative to their associated axes of rotation.

4. In a grounded training machine for aviators, .the combination of a manually operable training control simulating a similar form of control on an airplane and which control on the airplane is subjected to air stream forces of variable in- 8 tensity which tend to resist the manuallyY ari-5 plied force necessary to shift the airplane conf' trol, said training control mounted for rocking movement, mechanical means .including springs for imposing on the training control a 'rsistance toits otherwise freedom of movement and means for varying the point of application of force,` of saidrresistance relative to thev axis of rocking movement to vary the operative leverage through which the springs operate on the control and lthus `to simulate on the trainer .control the ef.

fects of the variable air stream forces which tend to resist the movement of the airplanek control.

ROBERT W. REFERENCES CITED The following references are of record in the le of this patent:`

UNITED STATES PATENTS` Great Britain 1918 

